Modern fax machines use C. SENSORS to transmit text.
A modern fax machines does not have rotating drums. Instead, it uses sensors to read the paper.
The modern fax machine has a photo-diode sensing array. It has at least 1,728 sensors so that when the paper is lit by a small fluorescent tube, the sensor can have a clear view of the black and white spots which it scans and transmits to the receiving end of the telephone line.